Download Earth Science Concepts

Branden Ollish Earth Science Concepts ™ Time measured over millions of years is called geologic time. This is how the history of the earth is recorded ™ Geologic time consists of four groups: Eons, Periods, Eras, and Epochs ™ Until a few hundred years ago it was thought that the earth was only a few thousand years old. In the 1800’s is was discovered that the earth was in face a few billion years old. ™ This was discovered using Relative dating, or telling when a random sample is from ™ Nicolaus Steno’s three laws: o Law of Superstition: Describes the undisturbed layers of rock over time o Law of Original Horizontality: Describes how layers of rocks form in a horizontal direction o Law of lateral continuity: Shows how water layered sediments slowly dissolve as they come closer to the edge of disposition ™ Continental plates are large plates created when pangea split apart ™ There are about 20 continental plates that make up the earth surface, all ranging in sizes ™ Plate Tectonics are a puzzle or plates that all apply pressure to each other in the earths lithosphere. ™ Plate tectonics also describes the forming and movement of oceanic and continental plates ™ A subduction zone is when two crustal plates collide forcing one of them to submerge into the mantle ™ Plate Boundarys; o Convergent: Plates crash together and one is forced under the other one. The plate is then pushed down into the mantle o Divergent: Plates pull apart from each other and make an opening for new lithosphere to rise up
Earthquakes ™ An earthquake is a slip of faults creating extremely powerful releases of seismic waves. ™ Seismic waves are caused by vibrations made when the rocks along the faults slip and slide ™ Hypocenter: The location below the surface where the rupture happens along the fault ™ Epicenter: The point right above the hypocenter on the earths surface ™ Earthquakes are known to cause mass destruction depending on their waves o P wave (primary wave): The fastest type of seismic wave. The denser the material, the faster the wave travels o S wave (secondary wave): Travels at 60 % of the speed of the p wave. Cannot travel through water, molten rock, and air ™ The power of an earthquake is judged by using the Richter magnitude scale Volcano ™ Volcanos are mounds or hills that occur over a plate boundary. ™ When lava rises up through the plate boundary and gets stuck under the surface pressure builds up. Once there is enough pressure the top of the volcano is blow off and lava is sent flying along with ash and gas. ™ Tephra: The technical term for all of the debris sent flying from a volcano ™ Volcanic ash can often be fatal and consist of all particulate smaller than 4mm in diameter ™ The gasses released from a volcano are often the most deadly part. Hot Spots ™ Hot spots are found over a chamber of high pressure and temperature magma. As the magma rises through vents large islands and mountains are formed like the Hawaiian islands